Shooting at Fort Hood Military Base

Lucy Hamlin and her husband, Spc. Timothy Hamlin wait for permission to re-enter the Fort Hood military base, where they live, following a shooting on base, April 2, 2014, in Fort Hood, Texas.

Tamir Kalifa/AP Photo

Lucy Hamlin and her husband, Spc. Timothy Hamlin wait for permission to re-enter the Fort Hood military base, where they live, following a shooting on base, April 2, 2014, in Fort Hood, Texas.

Tamir Kalifa/AP Photo

Soldiers listen in the wings as Lt. Gen. Mark Milley address the media during a news conference at the main gate to Fort Hood, Wednesday, April 2, 2014, in Fort Hood, Texas. A soldier opened fire, April 2, 2014, on fellow service members at the military base, killing three people and wounding 16 before committing suicide, authorities said.

Eric Gay/AP Photo

Lt. Gen. Mark Milley, the senior officer on base, speaks with the media outside of an entrance to the Fort Hood military base following a shooting that occurred inside, April 2, 2014, in Fort Hood, Texas. Four people were killed, including the gunman, and 16 were wounded in the attack, authorities said.

Tamir Kalifa/AP Photo

U.S. Secretary of Defense Chuck Hagel speaks about the shooting at Fort Hood during a news conference on the flight deck of the USS Anchorage (LPD-23), an amphibious transport dock ship, after a tour with his counterparts from Southeast Asia, April 2, 2014, at Joint Base Pearl Harbor-Hickam in Honolulu, Hawaii. Secretary Hagel is in Hawaii to host a meeting of defense ministers from the Association of Southeast Asian Nations (ASEAN). A MV-22 Osprey tiltrotor V/STOL aircraft is in the background.

Alex Wong/AP Photo

Krystina Cassidy and Dianna Simpson attempt to make contact with their husbands who are stationed inside Fort Hood, while standing outside of the Bernie Beck Gate, April 2, 2014, in Fort Hood, Texas.

Tamir Kalifa/AP Photo

A shooting has been confirmed on the Fort Hood military base in Killeen, Texas, April 2, 2014.

WFAA

A police officer checks drivers' IDs outside the main gate at Fort Hood, Texas, after a shooting at the Army base, April 2, 2014.

Deborah Cannon/Austin American-Statesman/AP Photo

A military police officer stops a car at Fort Hood, Texas, after a shooting on the Army base, April 2, 2014.

Deborah Cannon/Austin American-Statesman/AP Photo

A shooting has been confirmed on the Fort Hood military base in Killeen, Texas, April 2, 2014.

KWTX

President Barack Obama pauses as he speaks about the shooting at Fort Hood, April 2, 2014, in Chicago.

Carolyn Kaster/AP Photo

A shooting has been confirmed on the Fort Hood military base in Killeen, Texas, April 2, 2014.

Obtained by ABC News

A shooting has been confirmed on the Fort Hood military base in Killeen, Texas, April 2, 2014.

KWTX

Fort Hood has ordered everyone at the Texas Army base to "shelter in place," April 2, 2014.

AP Photo

The main gate at the U.S. Army post at Fort Hood, Texas is pictured in this undated photograph.